Low-intensity grids improve sensitivity of amsler grid testing in diabetic patients without background retinopathy.

We tested 22 eyes of 12 diabetic patients without retinopathy for visual loss using four types of Amsler grids. The Amsler grids, in order of decreasing intensity, were the standard white, bright red, fine red, and threshold (through cross-polarizing filters). The threshold grid detected the largest number of scotomas--16 versus 12, seven, and seven, respectively--and the largest total area of all scotomas--1594 degrees 2 of arc versus 1237, 994, and 927, respectively. In addition, metamorphopsia lessened as grid intensity decreased. These results demonstrate that the sensitivity of Amsler grid testing for visual loss in diabetics without retinopathy improves by decreasing the intensity of the grid used.